why tertiary winding in power transformer?

A tertiary winding in a power transformer serves several important functions. Primarily, it provides a path for unbalanced loads, helping to stabilize the system by reducing neutral currents. It can also be used for voltage regulation, supplying auxiliary power for station services, or connecting to a capacitor bank for power factor correction. Additionally, the tertiary winding can improve system reliability by offering a backup path for fault currents.